Liquid level indicator



May 26, 1936. I c. PYLE, 30., El AL 2,041,859

LIQUID LEVEL INDICATOR Filed Sept. 14, 1954 13 MERCURY PRESSURE GAUGE 5 "-6 PRESSURE LINE COMPENSATOR LINE HEATING EU. I

, Cyrus Pyle, 3rd

Russell T. VanNss wATTORNEY.

INVENTORS Patented May 26, 1936 LIQUID LEVEL INDICATOR Cyrus Pyle, 3d, Parlin, and Russell Terry Van Ness, Metuchen, N. J., assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation Delaware Application September 14, 1934, Serial No. 743,958

1 Claim.

This invention relates to apparatus for indicating the level of a liquid within a vessel and more particularly to a gauge for indicating the level of a boiling liquid under normal or abnormal a mospheric pressure of its own vapor.

Hydrostatic pressure gauges are commonly used for indicating the level of liquids in tanks, boilers, or other vessels, for example, the wellknown glass boiler gauge. These gauges are usually satisfactory where they may be installed in a position close to the tank which confines the boiling liquid. Such gauges may also be connected by air-tight pipes if the level indicator is situated at a distance from the tank but gauges are usually unsatisfactory where the liquid is boi1 ing, particularly if boiling violently, because the vapor produced by the boiling liquid condense in the pipes wherever a pocket is formed, or even in the sight glass, and therefore cause a false reading. The boiling liquid often dilutes the indicating liquid of the gauge, yielding incorrect readings.

The object of this invention is to provide an instrument which will indicate the correct level of a confined'boilingliquid. A further object is to provide an instrument which will indicate the correct level of a boiling liquid at a distance from the vessel in which the liquid is boiling. These objects are accomplished by introducing liquid overflow traps at equal levels above the two legs of a manometer gauge at the highest point'of the system.

The drawing shows diagrammatically the general plan of a suitable form of apparatus. In the drawing, I is a vessel which contains a boiling liquid indicated as 2. Near the bottom of the vessel and immersed in the liquid is a heating coil 3, which may be either a steam coil or an electricalheating unit. The vessel I is provided with a well 4, which is open at the bottom and closed at the top. Two pipes, 5 and 6, lead from the tube 4 toreservoirs I and 8, respectively, at the highest point in the system. These reservoirs are provided with two overflow cocks, 9 and I0. Pipes II and I2 lead from the base of the reservoirs l and 8, to the lower and upper ends respectively of a manometer tube I3 containing mercury. Two pipes, I4 and I5, lead from the reservoirs I and 8, to a three-way'valve I6 which is connected with an air pump II. Pipe 5 enters the well 4 and extends downwardly to the bottom of the liquid confined in the vessel I where it enlarges into a bell indicated as I8.

The apparatus is prepared for operation by filling the reservoirs I and B with the same liquid In the operation of the apparatus to determine I I the level of a boiling liquid, indicated as 2, air is blown from the pump I! through the valve II V and pipe I5 through pipe 6 into the well 4 and out small holes indicated as I9. in the upper part of the well. The valve I6 is then turned to cut oil the. air flowing in pipe I5 and adjusted to 3.1-; low air to flow through pipes I4 and 5 and out the bell I8. The purpose of this flow of air through these pipes is to sweep out all vapors of the boiling liquid. When this is done the valve I6 is closed. It is obvious that the surface of the mercury in gauge I 3 will now indicate the differential pressure between the bottom and the surface of liquid 2 in the vessel I. This manometer I3 may be suitably calibrated so that the level 01' v the liquid tube can be read thoroughly from. the

calibrated chart.

Liquid formed by the condensation. of the vapors from the boiling liquid can have no effect on the manometer reading, since the reservoirs I and 8 are already filled to overflowing with the same liquid, and any excess will flow back through the pipes 5 and 6 without having any influence on the reading of the manometer. It is apparent that the apparatus may be used for distillations carried out under sub or super atmospheric pressure as well as normal atmospheric pressure.

The apparatus may be placed in a position close to or remote from the vessel containing the boiling liquid. Other modifications will be apparent moval of water prior to the crystallization of inorganic salts, acids or bases.

This invention has an advantage over other de-. vices for indicating the level of liquids by the fact that it can be used for determining both boiling and non-boiling liquids in a closed vessel with exceptional accuracy where the heretofore known devices would be entirely unsuitable.-

It is apparent that many widely diilerent embodiments or this invention may be made without in each leg of the gauge, a. pipe communicating departing from the spirit and scope thereof and,- with the reservoir in one leg of the gauge and therefore, it is not intended to be limited exthe lower part of the interior of said vessel, a cept as indicated in the appended claim. second pipe communicating with the reservoir in 5 We claim: the other leg of the gauge and the space above 5 An apparatus for determining the level of a the liquid in said vessel, and an air pump comboiling liquid, comprising a. vessel adapted to conmunicating with each of said pipes whereby the tain a. boiling liquid under low super-atmossaid pipes are maintained free of liquid. pheric pressures and equipped with a V-tube CYRUS PYLE, 3RD. 0 liquid level gauge, a reservoir at the highest point RUSSELL TERRY VAN NESS. 10

CERTIFICATE or CORRECTION.

Patent No. 2,041,859 v May 26, 1936;

CYRUS PYLE, E AL.

It is hereby certified that error appears inthe printed specification of the above numbered patent requiring correction as fol-lows: Page 2,411 column, line 9, in the claim, for "V-tube" read Utub,e; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. I

Signed and sealed this 1st day of September, A. D. 195,6. i

. v Leslie Frazer (seal) I l A g mmi ne o lPate ts',

bodiments or this invention may be made without in each leg of the gauge, a. pipe communicating departing from the spirit and scope thereof and,- with the reservoir in one leg of the gauge and therefore, it is not intended to be limited exthe lower part of the interior of said vessel, a cept as indicated in the appended claim. second pipe communicating with the reservoir in 5 We claim: the other leg of the gauge and the space above 5 An apparatus for determining the level of a the liquid in said vessel, and an air pump comboiling liquid, comprising a. vessel adapted to conmunicating with each of said pipes whereby the tain a. boiling liquid under low super-atmossaid pipes are maintained free of liquid. pheric pressures and equipped with a V-tube CYRUS PYLE, 3RD. 0 liquid level gauge, a reservoir at the highest point RUSSELL TERRY VAN NESS. 10

CERTIFICATE or CORRECTION.

Patent No. 2,041,859 v May 26, 1936;

CYRUS PYLE, E AL.

It is hereby certified that error appears inthe printed specification of the above numbered patent requiring correction as fol-lows: Page 2,411 column, line 9, in the claim, for "V-tube" read Utub,e; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. I

Signed and sealed this 1st day of September, A. D. 195,6. i

. v Leslie Frazer (seal) I l A g mmi ne o lPate ts', 

